import java.util.Scanner;

/**
 * @author yuanbinbing
 * 求阶乘
例如：5！=5*4*3*2*1
 */
public class Task10_02 {
    public static void main(String[] args) {
        System.out.println("请输入一个数：");
        Scanner scanner=new Scanner(System.in);
        int x=scanner.nextInt();
        int result=1;
        for(int i=1; i<=x;i++){
            result=result*i;
        }
        System.out.println(result);
    }
}
